Oops. One error in there.
This fixes it:

--- /mnt/git/branch/heads/disfix2/tree/src/surface/plan9.c	Wed Feb  5 14:18:04 2020
+++ src/surface/plan9.c	Wed Feb  5 14:51:10 2020
@@ -113,7 +113,7 @@ plan9_set_geometry(nsfb_t *nsfb, int wid
 
 	/* select default sw plotters for format */
 	select_plotters(nsfb);
-	nsfb->plotter_fns->copy = p9copy;	/* empty function */
+	//nsfb->plotter_fns->copy = p9copy;	/* empty function */
 
 	drawstate_t *drawstate = nsfb->surface_priv;